Incandescent lamp.



T. A. WILLARD. l mmNpEscEN'r LAMP.

APPIJGATIOI FILED IEBA), 1910. BENEWED JAR. 24, 1912.

Patented Dee.24,19'12.

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j tion as possible, and also to so dispose the 'rnnononn A. WILLARD, or CLEVELAND, oHIo.

INCANDESCENT LAMP.

Specication of Letters Patent.

'Patented Dee. 24, 1912.

Application led February 9, 1910, Serial No. 542,983. Renewed January 24,'112. Serial No. 673,065

To all whom 'it may concern:

' Be itlrnown that I, THEODORE A. WIL- LARD, a citizen of the United States, and resident of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Incandescent Lamps, of which I hereby declare the following to be a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to -make and use the same.

The invention has reference to the use of incandescent' lamps for illuminating a parabolic reflector such as is employed" for the` as to fobtain the greatest amount of concen-- tration of'light in as nearly the focal Vposibases that the zone of shadow or interception of the rays oflight from one filamentcaused by the base of another lament will be dispersedby thelight from another fila- -menti j A further object is to reduce the size of the leading in wires by employin more vthan 4one set thereof, whereby a hig er candle power 'at a lowy voltagecan be obtained.

The employment of .a plurality of filaments in one lamp has the further advantage .inzadaptbility to railway-and automobile service that if one filament shouldbecome inefficient or; destroyed another can take its place and the entire loss of the use of the reiector. of" the headlight willfbe, avoided l tuted for the one destroyed. 15.

until a freslf base'or filament can be substi- Toaccomplish these objects aplurality of filaments and bases are' inserted in a coml I non bulb, and the filaments are adjusted'as closely together as possible therein .s o that they may be substantially'in thefocus of the parabola of thereector. Preferably one of the filaments should be actually located at I Y the focal point, and the other or 'others l should bej'as close to it as possible. When` J'thelam'ents are employed they and their;

light from the focal filament will be reflected in strictly parallel lines, and the rays of light from the outer filament will be reflected, in converging lines and therefore will tend to dissolve the shadow caused by the base of the outer filament.l When there are more than two filaments other forms of arrangement can be made to obtain the best, results. v

The invention further comprises the combination and arrangement of parts and manner ofconstruction of the various details as hereinafter descrlbed, shown inthe accome Y y other just in front of it, so that the rays ofl panying drawings and specifically pointed out in the claims.

In the accompanying, drawings Figure 1 is a vvertical central -section of a parabolic` reflector showing' a two lament or double being connected together in series; Fig. 2 is .a similar view showing the filaments connected in parallel; Fig. 3'shows an arrangement of three bases and filaments in one lamp; Fig..4 is an elevation'of contact device.

In these views 1 is the reflector, 'B the -each 4other and which are intercepted in a ,central zone-by the base 6 of the outer filaincandescent lamp therein, the filaments.

I nent which hence would cause a shadow in the center of the eld of illumination, at.-

w-m, and hence an imperfectl disclosure of the forms of objects in the path of the enthereon at a slightly sharper angle and will be reiected outwardly toward the axial line -of thefparabola instead of in linesv parallel jthere'with, thus tending tocompletely dissolve the-shadow caused by the base of theA gine. The light from the second filament 3 ;wil l vgreatly increasethe -illumination and 'since it is located slightly beyond the focal point of the 'reliector its rays '11 will fall 105l angle of 'reiection and become'V more perfect as the focus of these converging rays corresponds with the distance from the lamp of the objects which the lamp is designed to illuminate.- A

To make the suitable circuit connections,

with the outer filament and base,- the con-Y tacts shown in the figures may be employed.

l*These may be folding foradjustment of closely adjacent to, or substantially inthe focal point of the reflector, and when two are used they should bothof thembe preferably substantially in the focus or as close to it as possible.

`The angles of incidence and reflection -ing from the rays of light of the several fila-- ments will be slightlydiiferent and will cross each other, and therefore the rays from one of the outer filaments will tend to dissolve the shadow of its own base made in the path of the rays of light from the inner i1aments. Y

In 5 a two filamentV incandescent lamp 1s shown both iilaments being placed in as near the focal point as possible, or havmgit between them.

described" the invention, what I clalm as new and desire to secure byLetter's' Patent is:

1. In combination with a reflector, an ini-- candescent lamp therefor, comprising, a

bulb and a plurality of bases, leading in and filaments therefor, one filament beug locaited substantially at the focal point of e reflector, and another base and' fi1a ment located outside of said focal point, said filaments in axial line with each other, whereby the dow occasioned by the interposition of the second base in the reflected parallelrays oftherstlamentwill bedissolved by the non-parallelreilected rays of the second filament, and an adjustable con-,

tact device for said lamp. 2. In combination with d 1am a reetiiii mi.V canescent 'pcom'p" a ana plurality of bases, andlfnlaments' closely .approximated therein axial line, said ilaf `ments being located substantially in theY focal point 'of said reflector, whereby the' rays emanating'therefrom'will be reiiected vin lines substantially parallel to the axis of thereiector and an adjustable contact for one base. l

3; In combination with a reiiectcr, an incandescent lamp therefor, comprising, a luf rality of bases, leading in wires and a. A

ments, andA a common bulb therefor, one of said bases being inserted in the said reflector,

and its filament located in substantially the focalcenter of said reflector, whereby the angles of incidence and reflection are diier- Y lfrom said lila-v ent in Ythe rays emanating ments, and a folding contact device for the outer filament. j

4. In a lamp, a parabolic reiector, an incandescent lamp having a base securedf in the reflector, a filament for Vsaid lamp lo- A cated in the focal center of said reflector,

another filament therefor, located in the line 0f the axis of said reflector, outside/.ofsaid focal center, the reiiected rays of li hij emanating from the in a direction parallel to the'axis of the parabola, and the reiiected rays of light emahating from the secondA mentioned filament extending at an angle to said axial line, and an adjustable contact for said bulb;

5. In combination, a reiiector, an incandescent lamp therefor, a pl l number of filaments therein, a plural n r of bases and lea in wiresfor said acommon ulb, said ilamentsarranged substantially in the focal center of the reflector,

lirst named ilamen eirtend-V aments', and l l one of said bases secured in the said rellector, and an adjustable contact for said bulb.

`6. In combination with areilector, an im' candescent lamp bulb, a plurality of bases,

sockets' and filaments therein, one set of saidA 'bases and sockets secured in 'said reflector,

said filaments Y ed substantially inthe local point f the tricity,fa.ndA electrical vconnections whereby ly or simultane- 'ously caused to glow, said ulb. being ed axiall insaid reflector, to permit vof ector, a source of elec-flacing e'focus ofthe reflector between em. In'testimony whereof, I hereunto set my Yhand this 31 day of January, v1910. 

